Coal-screening apparatus.



A. W. CRAWFORD. GOAL SUREENING APPARATUS. 'APPLIUATION FILED AUG. 1o, 1905.

954,935. Faltante@ Apr. 12, 1910.

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A. W. CRAWFDRD.

GOAL SCREENING APPARATUS.

APPLICATION FILED AUG. 10, 1905. l

Patented Apr. 12, 1910.

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UNITED STATES PATENT OFFICE.

ALEXANDER W. CRAWFORD, 0F GIRARD, ILLINOIS.

GOAL-SCREENING APPARATUS.

Application filed August 1G, 1905. Serial No. 273,502.

To all whom it may concern:

Be it known that I, ALEXANDER W. CRAW- FORD, a citizen of the United States, residing in Girard, in the county of Macoupin and State of Illinois, have invented certain new and useful Improvements in Coal-Screening Apparatus, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to an apparatus for screening coal, whereby the coal may be screened into various grades according to the sizes of the linups present in the mass.

Briefly stated the apparatus consists of a plurality of screen plates suitably supported, mechanically operated means for conducting the coal over said screen plates to secure the screening action, means for delivering the coal to the screen, and means for conveying the various grades of coal from the apparatus.

Figure I is a top or plan view of my apparatus. Fig. II is a vertical longitudinal section taken through the coal receiving end of the apparatus. Fig. III is a vertical cross section taken on line III-III, Fig. II. Fig. IV is an enlarged perspective view of a fragment of one of the screen plates.A

Fig. V is an enlarged top or plan view of portions of a pair of abutting screen plates. Fig. VI is a longitudinal section taken on line VI*VI` Fig. V.

l designates the framework members of my apparatus by which the coal screening mechanism and the coal delivery members are supported. Mounted upon this framework adjacent to each end is a shaft 2, to either of which shafts power may be suitably applied. The shafts have fixed to them toothed wheels 3 (see Figs. II and III).

4t designates a pair of endless chains that are arranged to travel longitudinally of the apparatus and upon the toothed wheels 3. These chains have secured to them at intervals transversely extending carrier bars 5 that are preferably of angle form and each of which has one wing secured to links of the chains and the other wing extending at a right angle to the links to which the bar is secured.

6 designates a series of screen plates which are suitably supported beneath the conveyer consisting of the endless chains and the carrier bars 6. These screen plates may be of any desirable number and are arranged in a continuous course with their abutting ends overlapping and so placed, as seen in Figs. IV to VI inclusive, as to furnish a plain surface from one end of the series of plates to the other end of the series. Each of the screen plates is provided with a plurality of perforations 7, preferably of greater length than width, and extending downwardly and rearwardly from the bodies of the plates at such perforations, are inclined runways 8. The object of this construction is to permit of lumps of coal that are small enough to pass through the entirely open parts of the perforations descending therethrough without interference, and further to cause lumps of co-al that are too large to pass through the perforations but which lodge therein, to be carried onto the inclined runways 8 and travel upwardly and forwardly thereon when said lumps are engaged by other lumps which follow them upon the screen plates. This manner of dislodging the large lumps of coal is illustrated in Fig. VI. The perfo rations in the screen plates are of varying dimensions. Those in the plate at the receiving end of the apparatus, designated by the letter A see Figs. I and II, are of the smallest dimensions, while the perforations in each of the succeeding screen plates increase in dimensions to the rear end of the machine, designated by the letter B.

9 designates a delivery hopper through which the coal is delivered onto the first screen plate 6 at the receiving end of the apparatus to fall between the carrier bars 5 of the endless conveyer so that the carrier bars of said conveyer may conduct the coal along the series of screen plates in a direction toward the rear end of the machine.

I0 are delivery chutes, one of which is placed beneath each individual screen plate 6 and into which the coal that passes through each individual screen plate is conducted in its graded condition to a suitable point of delivery, whereby the various grades of lumps of coal are kept separated.

In the practical use of my apparatus, the coal to be screened is fed through the hopper 9 and falls upon the first screen plate at the receiving end of the apparatus. At this point it is caught by the carrier bars of the endless conveyer and conducted along the series of screen plates 6, the lumps of coal being screened through the perforations of the various screen plates according to their size, whereby the smaller lumps are first screened and those of greater and gradually increas' of perforations graduated in dimensions from end to end of the screen, of a mechanically actuated eonveyer operating above said screen to convey the material thereover during the "screening operation, said conveyer comprising a plurality of bars of an gle shape separated from each other to permit passage of material between them to the screen, each bar having one solid Wing adapted to lie flatly upony and traverse the screen in contact therewith and having another solid Wing extending at a right angle to the first Wing to engage and advance the material on the screen in a manner to prevent backward movement oli the material between 'the bars; substantially as set forth..

ALEXANDER WT. CRANVFORD.y In presence oill LOUIS F. LUENAGHI,

JAMES J. ODONNELL. 

